• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.25-33
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• 2002

Effect of surface topography on the water wetting nature and micro/nano tribological characteristics of Si-wafer and PTFE was experimentally studied. The ion beam treatment was performed with a hollow cathode ion gun in different argon don dose conditions in a vacuum chamber to change the surface topography, Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribo tester, SPM (scanning prove microscope), contact anglemeter and profilometer, respectively. Results showed that surface roughness increased with the argon ion dose. The water wetting angle of tile ion beam treated samples also increased with the ion dose. Results also showed that micro-adhesion and micro-friction depend on the wetting characteristics of the PTFE samples. However, nano-triboloSical characteristics showed little dependence on the wetting angles. The water wetting characteristics of modified PTFE samples were discussed in terms of the surface topographic characteristics.

• Journal of Surface Science and Engineering
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• v.34 no.1
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• pp.56-61
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• 2001

In this work, the surface treatment of aluminum/composites (graphite-epoxy composites) was investigated. The surface of composites was treated by $Ar^{+}$ ion beam under oxygen environment. The surface of aluminum was treated by DC plasma. The optimal condition of surface treatment for the composites was determined by measuring the contact angle as a function of ion dose. The optimal treatment condition of the aluminum was determined by measuring the contact angle and T-peel strength as a function of mixture ratio of acetylene gas to nitrogen gas. The mixture ratios used were 1:9, 3:7, 5:5, 7:3, and 9:1. The results showed that the contact angle of composites decreased from$ 81^{\circ}$ to $8^{\circ}$ as the ion dose increased from zero to $1$\times$10^{17}$ions/$\textrm{cm}^2$. The optimal condition of ion dose was $1$\times$10^{16}$ions/$\textrm{cm}^2$. The results also showed that the contact angle of aluminum was a minimum for the mixture ratio of 5:5. Similarly, the T-peel strength was a maximum for the mixture ratio of 5:5, which indicates that the optimal condition of mixture ratio of acetylene gas to nitrogen gas is 5:5.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.133.1-133.1
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• 2016

투명히터는 자동차유리 및 헤드램프의 성에 제거, 건축의 단열 및 난방, 의료용, 군사용 등 다양하게 사용되어지고 있으며, 더 나아가 플렉서블하고 웨어러블한 투명히터가 연구되고 있다. 투명히터에 사용되고 있는 대표적 투명전극인 Indium Tin Oxide (ITO)는 높은 투과도와 낮은 면저항을 가지지만 유연성이 좋지 않아 유연한 투명히터에 적용하기에는 어려움이 있다. 이를 해결하기 위해서 ITO를 대체할 수 있는 CNT, Graphene, AgNW, 전도성 고분자 등의 투명전극에 관한 연구가 활발히 진행되고 있다. 그러나 CNT, Grapene, 전도성 고분자는 여전히 전기적 특성이 좋지 못하기 때문에 차세대 투명전극으로 사용되기는 어려움이 있다. 반면에 AgNW는 용액공정으로 제조 단가가 비교적 저렴하며, 높은 전기전도 특성을 가지는 투명전극이다. AgNW는 나노와이어가 네트워크를 형성하고 있어 높은 전도성과 광 투과도를 가지지만 $200^{\circ}C$ 이상의 온도에서 손상된다. 이를 해결하기 위해 AgNW전극에 금속 산화막을 형성하여 내열성을 향상시키고자 하였다. 그러나 기존의 Reactive Sputter 방식으로 금속 산화막을 형성하게 되면 산소 분위기에서 AgNW가 산화되기 때문에 본 연구에서는 AgNW위에 금속 박막을 증착하고 Ion Beam 처리를 통해서 금속 산화막을 형성하여 AgNW 전극과 유사한 투과도와 저항을 가지면서 $300^{\circ}C$ 까지 열적 안정성을 확보하여 내열성을 향상시켰다. 유연한 PES기판 위에 스핀 코팅 방법으로 AgNW를 코팅하였고, Magnetron Sputter로 금속 박막을 형성한 후 Ion Beam 처리를 통해 금속 산화막을 형성하였다. 이를 적용하여 투명히터를 제작한 결과 유연 기판상 투명히터로 활용이 가능함을 확인하였다.

• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.10-13
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• 2005

$Sr_{0.6}Ba_{0.4}Nb_{2}O_{6}$, hereafter SBN60, thin films of 300 nm thickness were deposited using ion beam sputtering technique, in which sintered ceramic target of the same composition was utilized and the $Ar:O_{2}$ gas ratio was controlled during deposition onto $Pt(100)/TiO_{2}/SiO_{2}/Si$ substrate. Crystallization and orientation behavior as well as electrical properties of the films were examined after annealing treatment at $650{\sim}800{\cric}C$. It was found that the film orientation was dependent upon $Ar:O_{2}$ratio, in which strong (00l) orientation was developed when the gas ratio was about 1:4 at $4.3{\times}10^{-4}$ torr. Typical remanent polarization (2Pr), the coercive field (Ec) and the dielectric constant of Pt/SBN60/Pt thin film capacitor were approximately $10{\mu}C/cm^{2}$, 60 kV/cm, and 615, respectively.

• Journal of Surface Science and Engineering
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• v.53 no.3
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• pp.116-123
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• 2020

Ion beam irradiation induces self-organization of nanostructure on the surface of polymer film. We show that the incident angle of Ar ions on polyethylene naphthalate(PEN) film changes self-organized nanostructure. PEN film was irradiated by argon ion beams with the ion incident angle of 0°, 30°, 45°, 60°, and 80°. Nanostructure was altered from dimple to ripple structure as the angle increases. The ripple structure changed to pillar structure after 60°due to that the shallow incident angle increased the ion energy transfer per depth up to 50 eV/Å, which value could induce excessive surface heating and oligomer formation reacting as a physical mask for anisotropic etching. And quantitative analysis of the nanostructures was adapted by using ABC model and fractal dimension theory.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.704-723
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• 2000

This study was undertaken to evaluate the tensile bond strength of In-Ceram alumina core treat-ed by ion assisted reaction(IAR). Ion assisted reaction is a prospective surface modification technique without damage by a keV low energy ion beam irradiation in reactive gas environments or reactive ion itself. 120 In-Ceram specimens were fabricated according to manufacturer's directions and divided into six groups by surface treatment methods of In-Ceram alumina core. SD group(control group): sandblasting SL group: sandblasting + silane treatment SC group: sandblasting + Siloc treatment IAR I group: sandblasting + Ion assisted reaction with argon ion and oxygen gas IAR II group: sandblasting + Ion assisted reaction with oxygen ion and oxygen gas IAR III group: sandblasting + Ion assisted reaction with oxygen ion only For measuring of tensile bond strength, pairs of specimens within a group were bonded with Panavia 21 resin cement using special device secured that the film thickness was $80{\mu}m$. The results of tensile strength were statistically analyzed with the SPSS release version 8.0 programs. Physical change like surface roughness of In-Ceram alumina core treated by ion assistad reaction was evaluated by Contact Angle Measurement, Scanning Electron Microscopy, Atomic Force Microscopy; chemical surface change was evaluated by X-ray Photoelectron Spectroscopy. The results as follows: 1. In tensile bond strength, there were no statistically significant differences with SC group, IAR groups and SL group except control group(P<0.05). 2. Contact angle measurement showed that wettability of In-Ceram alumina core was enhanced after IAR treatment. 3. SEM and AFM showed that surface roughness of In-Ceram alumina core was not changed after IAR treatment. 4. XPS showed that IAR treatment of In-Ceram alumina core was enabled to create a new functional layer. A keV IAR treatment of In-Ceram alumina core could enhanced tensile bond strength with resin cement. In the future, this ion assisted reaction may be used effectively in various dental materials as well as in In-Ceram to promote the bond strength to natural tooth structure.

• Proceedings of the Korean Vacuum Society Conference
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• 2003.02a
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• pp.208-208
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• 2003

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.620-631
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• 2015

A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC $43971^T$, Micrococcus luteus ATCC $4698^T$ and Escherichia coli ATCC $11775^T$ were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at $100^{\circ}C$), but the antimicrobial activity was eliminated after treatment at $121^{\circ}C$ for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.456-461
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• 2007

In this study, a surface treatment method using accelerated Ar ions was experimented for exposing the carbon nanotubes (CNT) from the screen-printed CNT paste. After making a cathode electrode on the glass substrate, photo sensitive CNT paste was screen-printed, and then back-side was exposed by UV light. Then, the exposed CNT paste was selectively remained by development. After post-baking, the remained CNT paste was bombarded by accelerated Ar ions for removing some binders and exposing only CNTs. As results, the field emission characteristics were strongly depended on the accelerating energy, bombardment time, and the power of RF plasma ion source. When Ar ions accelerated with 100 eV energy from the 100 W RF plasma source are bombarded on the CNT paste surface for 10 min, the emission level and the uniformity were best.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.192-194
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• 2002

We investigated the surface treatment of spectra fibers to improve tensile properties of spectra/vinylester composites. The spectra fibers were surface-treated using $\textrm{Ar}^{+}$ ion beam under oxygen environment. The treatment effect of spectra fibers on the tensile properties of spectra/vinylester composites was determined comparing the residual strength of surface-treated spectra/vinylester composites with that of untreated spectra/vinylester composites. It was found that the residual strength was improved 15% by the surface treatment of spectra fibers.